Bug 2124013

Summary: Incorrect rendering triggered by cairo CAIRO_OPERATOR_SATURATE with subpixel positioning
Product: Red Hat Enterprise Linux 8 Reporter: Benjamin Gilbert <bgilbert>
Component: pixmanAssignee: Adam Jackson <ajax>
Status: NEW --- QA Contact: Desktop QE <desktop-qa-list>
Severity: unspecified Docs Contact:
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Version: CentOS StreamCC: bstinson, jwboyer, ndegraef
Target Milestone: rcFlags: bgilbert: needinfo? (ndegraef)
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Test program none

Description Benjamin Gilbert 2022-09-03 23:00:02 UTC 
Created attachment 1909395 [details]
Test program

Description of problem:
pixman 0.38.x has a regression that causes incorrect rendering in some circumstances.  This can be triggered by the use of cairo with CAIRO_OPERATOR_SATURATE and subpixel positioning, and causes OpenSlide <https://openslide.org/> to produce incorrect output.

Version-Release number of selected component (if applicable):
0.38.4-2.el8.x86_64

How reproducible:
Always

Steps to Reproduce:
Compile and run attached test program.

Actual results:
Program prints "Failed"

Expected results:
Program prints "OK"

Additional info:
This is fixed upstream in https://gitlab.freedesktop.org/pixman/pixman/-/commit/8256c235d9b3854d039242356905eca854a890ba, which is in pixman 0.40.0.
Comment 1 Benjamin Gilbert 2022-09-10 05:26:05 UTC 
Fix posted in https://gitlab.com/redhat/centos-stream/rpms/pixman/-/merge_requests/2.